WO2011135321A1 - Optical fibre coupler - Google Patents
Optical fibre coupler Download PDFInfo
- Publication number
- WO2011135321A1 WO2011135321A1 PCT/GB2011/050615 GB2011050615W WO2011135321A1 WO 2011135321 A1 WO2011135321 A1 WO 2011135321A1 GB 2011050615 W GB2011050615 W GB 2011050615W WO 2011135321 A1 WO2011135321 A1 WO 2011135321A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- fibres
- fibre
- combiner
- section
- stacks
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
- G02B6/2856—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers formed or shaped by thermal heating means, e.g. splitting, branching and/or combining elements
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
- G02B6/4401—Optical cables
- G02B6/4403—Optical cables with ribbon structure
- G02B6/4404—Multi-podded
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
- G02B6/4401—Optical cables
- G02B6/441—Optical cables built up from sub-bundles
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
- G02B6/4401—Optical cables
- G02B6/441—Optical cables built up from sub-bundles
- G02B6/4411—Matrix structure
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49826—Assembling or joining
Definitions
- This invention relates to optical apparatus.
- it relates to a combiner for combining the output of a plurality of emitter diodes such as laser diodes into a single output.
- High power diode laser manufacturers commonly use diode laser bars as a primary source of laser power and free-space micro-optical methods to combine many individual laser emitters suitable for direct use or for launch into a beam delivery fibre. However, this involves the use of many precision aligned components, resulting in high complexity and cost.
- Fibre-coupling of the single-emitters and subsequent fibre-combining is an attractive approach as it simplifies the optical arrangement required.
- most schemes use optical fibres with a circular core cross-section and hence introduce a significant loss of brightness - typically this involves 30 times brightness reduction.
- the present invention arose in an attempt to provide an improved system which better conserves the brightness of combined fibre-coupled single emitter laser diodes, particularly for direct diode systems and fibre lasers. More specifically, the present invention describes fibre-combining schemes which combine more than one input fibre with a rectangular core cross-section into a single output fibre with a circular core cross-section.
- an optical combiner comprising a plurality of input optical fibres which have a non-circular cross-section, the fibres having a proximal end for receiving light from a respective diode emitter and a distal end, the fibres being combined at their distal ends and joined to a single circular output fibre, whereby in use light from a plurality of diode emitters is combined and output through the single output fibre.
- the input fibres are preferably rectangular or substantially rectangular in cross-section.
- the output fibre is preferably circular or substantially circular in cross-section.
- An outer capillary may be arranged circumferentially around at least the distal end of a stack or bundle of fibres, and/or around at least the distal end of all the fibres.
- an optical combiner comprising a plurality of input optical fibres which have a non- circular cross-section, the fibres having a proximal end for receiving light from a respective diode emitter and a distal end, the fibres being combined at their distal ends and joined to a single output fibre, whereby in use light from a plurality of diode emitters is combined and output through the single output fibre.
- the input fibres are rectangular or substantially rectangular in cross-section.
- the output fibre is preferably circular or substantially circular in cross-section.
- a capillary may be mounted around at least the portion of the fibres which are fused to form the combiner. Alternatively, and/or additionally, a capillary may be mounted around each stack or bundle of fibres.
- Figure 1 shows a combiner arrangement
- Figure 2 shows a cross-section through an arrangement of optical fibres
- Figure 3 shows a cross-section through an arrangement of optical fibres
- Figures 4(a) to 4(d) show manufacturing steps
- Figure 5 shows a rectangular 5 by 1 linear stack of fibres
- Figure 6 shows a stack of 7 fibres
- Figure 7 shows an array of 15 fibres
- Figure 8 shows an array of 7 circular fibres
- Figure 9 shows an array of 3 circular fibres
- Figure 10 shows an array of 9 rectangular fibres
- Figure 11 shows an arrangement in which input fibres are not arranged in stacks.
- An array A of single emitter laser diodes Dl, D2 ... Dn are arranged to emit laser outputs to an array of N rectangular or other generally elongate cross section fibres Fl, F2 ... Fn, each diode emitting into a respective one of the fibres Fl , F2 ... Fn. Note that in certain embodiments there may be only two such fibres or any number more than two.
- the outputs from the lasers are emitted into free proximal ends 4 of fibres.
- the fibre Fl, F2 ... Fn are fused together to a circular fibre 8, which then carries the combined laser or other light energy from the diode.
- a combiner 7 is thus formed where the input fibres are fused and joined to the output fibre.
- the single circular fibre 8 provides an output carrying the combined output of the N times laser diodes. This may be used on its own or for pumping a fibre laser or for many other purposes.
- the cross-section of the input fibres Fl to Fn and their aspect ratio is designed to better match the geometry of a diode facet than previous circular designs. It is most preferably rectangular or substantially rectangular. They may have curved ends or corners for example but will still be substantially rectangular. A fibre with rectangular or other elongate cross- sections reduces the loss of brightness at the fibre coupling stage. It is believed that the factor by which brightness is maintained may be five to ten times more than with circular fibres, although it may be more or less than this range.
- the process of combining the output from two or more input fibres into a single output fibre usually leads to a decrease in the brightness of the light, due to the combined cross- sectional area of the cores of the input fibres being less than or equal to the cross-sectional area of the core of the output fibre.
- the fill-factor of the combiner (equal to the ratio of the input to output core cross-sectional areas) has a value less than or equal to unity.
- A; is the core cross-sectional area of the individual fibres
- B is the core cross-sectional area of the output fibre:
- the value of this fill-factor will vary for different combiner geometries.
- the brightness of the diode without coupling fibre is approximately 50MW/cm .sr.
- the rectangular fibre output has approximately 4.2 times the brightness of the circular fibre.
- the following table shows examples of the brightness that can be obtained with different combiner configurations, for both of the fibre types described above.
- the close-packed hexagonal geometry (e.g. Example #2 in the table above) is particularly attractive, since it has both a relatively high fill-factor and is also straightforward to achieve in practise.
- the most readily produced arrangement for rectangular cross-section fibres is a linear stack (such as that of Figures 3, 5 or 6).
- the fill-factor 0.64.
- the fill-factor will be less than 0.64 (e.g. Examples #3 and #4 in the table above).
- input fibres with a cladding present will also have a fill-factor less than 0.64.
- the present invention seeks to better preserve the input brightness of a rectangular-fibre combiner by presenting alternative geometries that have an improved fill-factor when compared to the fill-factor of a linear stack of rectangular fibres i.e. geometries with a fill- factor exceeding 0.64.
- a fill-factor exceeds 0.64.
- 9: 1 combiner shown in Figure 6 where 7 fibres are arranged in a linear stack and two additional fibres have been rotated by 90 degrees and placed on the sides of this stack.
- the fill-factor is reduced to 0.73 and so the output brightness is 4.9MW/cm /sr. This represents an improvement of nearly 16% over a linear-stack combiner geometry comprised of 5 of these rectangular fibres.
- a further example is the 15:1 combiner shown in Figure 7.
- a bundle of 5 fibres is arranged in an angled-stack; 3 such stacks are then arranged as shown.
- This example has a fill- factor equal to 0.78 for the rectangular fibres described above with an output brightness of 4.9MW/cm /sr. This represents an improvement of nearly 24% over a linear-stack combiner geometry comprised of 5 of these rectangular fibres.
- an outer capillary 11 is provided to provide a convenient and innovative way of retaining the fibres prior to fusion.
- non-circular fibres are arranged in a highly-organised manner in order to produce an enhanced fill-factor. They may be allowed to take up any arbitrary arrangement with each other.
- the fibres 'self-organise' into a close-packed geometry.
- the fibres are not arranged in well-defined stacks and do not display any form of symmetry.
- An example is the 17:1 combiner shown in figure 11. This example shows non-circular fibres with dimensions 100x33 ⁇ arranged within an outer capillary. In this example, the fill- factor equals 0.70 and so still exceeds that of a regular square stack of fibres. Many other configurations will be apparent.
- the bundles of fibres in the chosen configuration are fused at their distal end and combined with a single output fibre such that signals passing via each of the fibres is output through the single output fibre.
- the use of an outer capillary as a fixturing tool to bundle together a number of rectangular fibres allows a combiner to be more readily assembled and also reduces the risk of damage and/or contamination.
- Figure 4 shows schematically how a combiner can be manufactured.
- a bundle of fibres which may have 105 x 20 ⁇ cores and 125 x 40 ⁇ cladding are provided.
- three bundles are provided and these may be in 3 x 5 arrangement as in Figure 2, 3 x 7, 3 x 9 or any other configuration.
- Each of the fibres is initially provided separately.
- each of the fibres is etched, typically in a HF (hydrofluoric) acid, to remove most of the cladding layer.
- a bundle of five fibres, arranged in a linear stack, with the etched ends protruding, is loaded into a short section of capillary which, for this size of fibre, may be of 282 ⁇ inner diameter.
- the five fibres in the stack are fixed into the capillary of any convenient method such as using adhesive or light fusion.
- the capillary is attached to the unetched portion of the fibres.
- a typical stack at this stage will have an appearance as shown schematically in Figure 3.
- a relatively long section of a larger-bore capillary (OD in range 1.0 - 1.5mm) which may typically be of about 100 mm in length is prepared with two tapered portions applied somewhere between its two ends, typically in the middle.
- the first of these may have an inner diameter of the tapered section of 615 ⁇ and the second of these tapered sections (which preferably lies within the first) may have an inner diameter of 230 ⁇ .
- the first tapered section is intended to accommodate the 3 capillary sections produced in the third step.
- the second tapered portion is intended to accommodate the etched fibres that protrude from these separate stacks.
- a fifth step three of the stacks form in step 3 are loaded into the long section of capillary prepared in step 4 (to produce a configuration generally as shown in Figure 2).
- the fibres in each stack will initially form a linear stack (as per figure 3)
- the fibres will assume the angled (offset) geometry shown in Figure 2 (where respective fibres in a stack are offset one from each other) due to being guided by the inner wall of the tapered section of the capillary 11.
- the bundle of fibres and capillary is fused and tapered at a waist 13 within the tapered part 12 to provide a waist of a desired diameter, such as 187 ⁇ .
- a desired diameter such as 187 ⁇ .
- a seventh step shown in Figure 4(c) the fused bundle is cleaved at a cleave point 14 at the waist.
- the cleaved assembly is spliced to a desired output fibre 15 [which will generally be a circular core fibre].
- the core diameter could be 150 ⁇ and the cladding diameter 165 ⁇ , with a core NA value equal to 0.22.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Couplings Of Light Guides (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/642,426 US20130094809A1 (en) | 2010-04-30 | 2011-03-25 | Optical fibre coupler |
EP11711623A EP2564249A1 (en) | 2010-04-30 | 2011-03-25 | Optical fibre coupler |
JP2013506740A JP2013525853A (en) | 2010-04-30 | 2011-03-25 | Optical device |
CN2011800218627A CN102906611A (en) | 2010-04-30 | 2011-03-25 | Optical fibre coupler |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1007253.6 | 2010-04-30 | ||
GBGB1007253.6A GB201007253D0 (en) | 2010-04-30 | 2010-04-30 | Optical apparatus |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2011135321A1 true WO2011135321A1 (en) | 2011-11-03 |
Family
ID=42289898
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB2011/050615 WO2011135321A1 (en) | 2010-04-30 | 2011-03-25 | Optical fibre coupler |
Country Status (6)
Country | Link |
---|---|
US (1) | US20130094809A1 (en) |
EP (1) | EP2564249A1 (en) |
JP (1) | JP2013525853A (en) |
CN (1) | CN102906611A (en) |
GB (1) | GB201007253D0 (en) |
WO (1) | WO2011135321A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1990014316A1 (en) * | 1989-05-17 | 1990-11-29 | National Research Development Corporation | Process for the manufacture of objects with small complex cross-sections |
EP0893862A2 (en) * | 1997-07-21 | 1999-01-27 | Lucent Technologies Inc. | Tapered fiber bundles for coupling light into and out of cladding-pumped fiber devices |
EP1054276A1 (en) * | 1999-05-20 | 2000-11-22 | Lucent Technologies Inc. | Article comprising a fiber bundle, and method of making the article |
WO2006078638A2 (en) * | 2005-01-21 | 2006-07-27 | Ceramoptec Industries, Inc. | Compact bundles of light guides with sections having reduced interstitial area |
DE102008020828A1 (en) * | 2008-04-25 | 2009-10-29 | Jt Optical Engine Gmbh + Co. Kg | fiber coupler |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6321013B1 (en) * | 1999-09-15 | 2001-11-20 | Lucent Technologies, Inc. | Stacks of optical fiber ribbons closely bound by respective buffer encasements, associated methods, and associated fiber optic cables |
US6870995B2 (en) * | 2001-07-05 | 2005-03-22 | Pirelli Cables And Systems Llc | High fiber count optical fiber cable with buffer tubes around central strength member |
JP2004325550A (en) * | 2003-04-22 | 2004-11-18 | Fujikura Ltd | Light converging mechanism, semiconductor laser device and optically excited solid laser |
-
2010
- 2010-04-30 GB GBGB1007253.6A patent/GB201007253D0/en not_active Ceased
-
2011
- 2011-03-25 JP JP2013506740A patent/JP2013525853A/en active Pending
- 2011-03-25 EP EP11711623A patent/EP2564249A1/en not_active Withdrawn
- 2011-03-25 WO PCT/GB2011/050615 patent/WO2011135321A1/en active Application Filing
- 2011-03-25 CN CN2011800218627A patent/CN102906611A/en active Pending
- 2011-03-25 US US13/642,426 patent/US20130094809A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1990014316A1 (en) * | 1989-05-17 | 1990-11-29 | National Research Development Corporation | Process for the manufacture of objects with small complex cross-sections |
EP0893862A2 (en) * | 1997-07-21 | 1999-01-27 | Lucent Technologies Inc. | Tapered fiber bundles for coupling light into and out of cladding-pumped fiber devices |
EP1054276A1 (en) * | 1999-05-20 | 2000-11-22 | Lucent Technologies Inc. | Article comprising a fiber bundle, and method of making the article |
WO2006078638A2 (en) * | 2005-01-21 | 2006-07-27 | Ceramoptec Industries, Inc. | Compact bundles of light guides with sections having reduced interstitial area |
DE102008020828A1 (en) * | 2008-04-25 | 2009-10-29 | Jt Optical Engine Gmbh + Co. Kg | fiber coupler |
Also Published As
Publication number | Publication date |
---|---|
JP2013525853A (en) | 2013-06-20 |
GB201007253D0 (en) | 2010-06-16 |
US20130094809A1 (en) | 2013-04-18 |
EP2564249A1 (en) | 2013-03-06 |
CN102906611A (en) | 2013-01-30 |
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